Oculomotor nerve is the third cranial nerve (CN III). It enters the circle through the superior orbital fissure  and innervates outward eye muscles that empower most movements of the eye and that raise the eyelid. The nerve also contains fibers that innervate the intrinsic eye muscles that empower pupillary narrowing and convenience . The oculomotor nerve is derived from the basal plate of the embryonic midbrain. Cranial nerves IV and VI also participate in control of eye movement.

Structure: 

The oculomotor nerve originates from the third nerve nucleus  at the level of the superior colliculus in the midbrain. The third nerve nucleus is found ventral to the cerebral aqueduct, on the pre-aqueductal dark matter. The fibers from the two third nerve cores found horizontally on one or the other side of the cerebral water channel then, at that point go through the red core. From the red core strands then, at that point pass by means of the substantia nigra leaving through the interpeduncular fossa.

On rising up out of the brainstem, the nerve is contributed with a sheath of pia mater, and encased in a prolongation from the arachnoid. It passes between the predominant cerebellar (underneath) and back cerebral corridors (above), and afterward punctures the dura mater foremost and horizontal to the back clinoid measure, passing between the free and connected boundaries of the tentorium cerebelli.

It crosses the enormous sinus, over the other orbital nerves getting in its course a couple of fibers from the huge plexus of the thoughtful sensory system, and a conveying branch from the ophthalmic division of the trigeminal nerve.

Superior branch:

The superior part of the oculomotor nerve or the prevalent division, the more modest, ignores medially the optic nerve. It supplies the superior rectus and levator palpebrae superioris.

Inferior branch:

The Inferior part of the oculomotor nerve or the second rate division, the bigger, separates into three branches.

• One passes underneath the optic nerve to the average rectus.
• Another, to the substandard rectus.
• The third and longest runs forward between the substandard recti and lateralis to the sub-par sideways.
• From the third one, a short thick branch is radiated to the lower part of the ciliary ganglion, and structures its short root.

This load of branches enter the muscles on their visual surfaces, except for the nerve to the substandard sideways, which enters the muscle at its back line.

Nuclei:

The oculomotor nerve (CN III) emerges from the foremost part of mesencephalon (midbrain). There are two cores for the oculomotor nerve:

• The oculomotor nucleus originates at the level of the superior colliculus. The muscles it controls are the striated muscle in levator palpebrae superioris and all extraocular muscles except for the superior oblique muscle and the lateral rectus muscle.
• Edinger-Westphal nucleus supplies parasympathetic fibers to the eye via the ciliary ganglion, and thus controls the sphincter pupillae muscle and the ciliary muscle.

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Regards
Alina Grace
Managing Editor
Journal of Anatomical Science and Research.